The present invention relates to a method for providing functions within an industrial automation system. The invention furthermore relates to a computer program product. The invention furthermore relates to an industrial automation system.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Industrial automation systems are used to monitor, control and regulate technical processes, particularly in the field of production, process and building automation, and enable an operation of control units, sensors, machinery and industrial plants which is intended to be performed as autonomously and as independently from human intervention as possible. Due to the constantly increasing importance of information technology for automation systems having numerous networked control and computer units, methods for the reliable provision of functions distributed over an automation system are becoming increasingly important for a provision of monitoring, control and regulating functions.
A multiplicity of control units, also known as PLCs (Programmable Logic Controllers), can be used in an industrial automation system. Each control unit normally provides an interface via which the respective control unit can be accessed. A multiplicity of different information elements can be retrieved via the interface, such as a current status of the control unit, configuration data of the control unit, system and user variables, diagnostic information (such as traces, alarms, logs, etc.) or a backup of a current configuration of the control unit. It is possible in some instances not only to view data but also to access and modify these data via the interface.
A web application which enables the access via http or https is installed on the control unit for this purpose. To do this, for example, individual web pages can be stored in a memory in the control unit, said pages enabling the connection to the aforementioned data and/or states of the control unit. The information is resolved in runtime on the control unit side in each case on retrieval of the respective web page and is integrated into the latter. The web page is then transmitted to a web client. A web page containing the requested data is thus created for each request from a web client.
One problem with this approach is that the web application has a very high complexity. In addition, a respective number of web pages with data integrated therein must be provided for each different control unit type. It is furthermore disadvantageous that the updating of the data on the web pages requires the reloading of the web page concerned. This may be done automatically when a web page is retrieved, for example while navigating through a plurality of pages, wherein the reloading is prompted explicitly by a user. Alternatively, an update can be performed at fixed intervals, e.g. every five seconds. As a result, a high computing load for the web application is thereby generated. From the perspective of the user, this results in a poor response time.
A Single-Page Application (SPA) refers to a web application which consists of a single HTML document and whose contents are dynamically reloaded. With a Single-Page Application, a user no longer needs to switch between individual web pages. Instead, interactions with the web application in a terminal device on the client side result in communication in the background which dynamically reloads further components of the single web page. Data can also be reloaded via different proprietary interfaces.